Certified Rhythm Analysis Technician (CRAT) Practice Exam

In this scenario, it is important to understand how a pacemaker functions and interacts with the heart's own electrical conduction system. The electronic pacemaker is set to generate impulses at a rate of 72 beats per minute (bpm), which means it is designed to stimulate the heart to beat at that frequency.

However, the AV node, which is part of the heart's electrical system responsible for relaying impulses from the atria to the ventricles, is firing at a lower rate of 58 bpm. In a normal situation, if the intrinsic pacing of the AV node (or any other inherent pacemaker in the heart) falls below the set rate of the pacemaker, the pacemaker takes over and ensures the heart rate remains at its set rate.

Since the pacemaker is functioning properly and is set at a rate of 72 bpm, and the heart's natural pacemaker (the AV node, in this case) is firing slower at 58 bpm, the pacemaker will dominate in controlling the heart rate. Therefore, the patient's heart rate will be determined by the pacemaker, resulting in a heart rate of 72 bpm, which is consistent with the setting of the electronic pacemaker.